JP6770217B2 - A method for producing a solid electrolytic capacitor and a method for producing a dispersion containing a conjugated conductive polymer. - Google Patents

Description

The present invention relates to a method for producing a solid electrolytic capacitor and a method for producing a dispersion liquid containing a conjugated conductive polymer.

A solid electrolytic capacitor has been proposed in which a dielectric oxide film is formed on a metal surface by anodization and a solid electrolyte is brought into contact with the film, and a conductive polymer is used as the solid electrolyte.

Aluminum, tantalum, niobium and the like are known as examples of metals covered with a dielectric oxide film by anodization.
Conjugated conductive polymers such as polythiophene, polypyrrole, polyaniline, polyacetylene, polyphenylene, poly (p-phenylene-vinylene), polyacene, polythiophene vinylene and derivatives thereof are known as conductive polymers used in solid electrolytic capacitors. Has been done. Further, a technique of doping a conjugated conductive polymer with a polyanion such as polystyrene sulfonic acid as a counter anion of the conjugated conductive polymer is known.

As a general method for forming a solid electrolyte, a monomer compound solution and an oxidizing agent solution are chemically oxidatively polymerized or electrolyzed on a dielectric oxide film formed on the surface of a metal having a valve action (valve action metal). Examples include a method of polymerization. Further, as a method for forming a solid electrolyte, a method of applying a conductive polymer aqueous solution or suspension to a valve acting metal on which a dielectric oxide film is formed has been proposed.

For example, Patent Document 1 describes a step of impregnating a condenser element with a conductive polymer dispersion aqueous solution in which fine particles of a conductive polymer are dispersed to form a first solid electrolyte layer, and a step of forming the first solid electrolyte layer. The surface of the second solid electrolyte is impregnated with a solution containing a heterocyclic monomer and a solution containing an oxidizing agent individually, or by impregnating a mixed solution containing a heterocyclic monomer and an oxidizing agent. A method for manufacturing a solid electrolytic capacitor including a step of forming a layer is disclosed.

In Patent Document 2, a conductive polymer layer is formed as a solid electrolyte layer by chemically polymerizing a polymerizable monomer on a capacitor element having a dielectric oxide film formed on the surface of a sintered body obtained by sintering a valve metal powder. After that, a method for manufacturing a solid electrolytic capacitor including a step of immersing the capacitor element in a conductive polymer solution or applying a conductive polymer solution and drying the capacitor element is disclosed.

Patent Document 3 proposes a process of polymerizing poly (3,4-ethylenedioxythiophene) -polystyrene sulfonic acid (PEDOT-PSS) by using ultrasonic irradiation.

Patent Document 4 discloses a step of polymerizing a monomer compound in a dispersion medium containing seed particles protected and colloidalized with a monomer compound and a polyanion to obtain a conjugated conductive polymer-containing dispersion. ing.

Japanese Unexamined Patent Publication No. 2003-100561 Japanese Unexamined Patent Publication No. 2005-109252 Japanese Patent Publication No. 2011-510141 International Publication No. 2014/163202

However, these prior arts have room for further improvement in capacity expression rate (capacitance) and equivalent series resistance (ESR) performance.
An object of the present invention is to provide a solid electrolytic capacitor having a high capacitance expression rate (capacitance) and a low equivalent series resistance (ESR), and a method for manufacturing the same.
Further, the present invention provides a method for producing a dispersion liquid containing a conjugated conductive polymer, which is useful for producing a solid electrolytic capacitor having a high capacitance expression rate (capacitance) and a low equivalent series resistance (ESR). The purpose is to do.

As a result of diligent research, the present inventors have solved the complex formed by the conjugated conductive polymer and the polyanion in the manufacturing process of the conjugated conductive polymer dispersion used as the solid electrolyte of the solid electrolytic capacitor. We have found that the above problems can be solved by suspending the dispersion treatment of the dispersion liquid containing these in order to efficiently perform the aggregation, and completed the present invention.

That is, the present invention relates to a method for producing a solid electrolytic capacitor according to the following [1] to [15], a method for producing a solid electrolytic capacitor, and a method for producing a dispersion liquid containing the conjugated conductive polymer according to the following [16].
[1]
A method for manufacturing a solid electrolytic capacitor having a porous anode made of a valve acting metal having a dielectric film on its surface and a solid electrolyte layer provided on the surface of the dielectric film.
A monomer compound for obtaining a conjugated conductive polymer is polymerized in a liquid containing a polyanion and an aqueous medium to obtain a dispersion liquid (1) containing the conjugated conductive polymer, and the dispersion liquid is obtained. A step (A) of subjecting (1) to a dispersion treatment to obtain a dispersion liquid (2) containing the conjugated conductive polymer.
The step (B) of adhering the dispersion liquid (2) to a porous anode made of a valve acting metal having a dielectric film on the surface, and the aqueous dispersion liquid (2) adhering to the porous anode body. Step of removing the medium to form a solid electrolyte layer (C)
Have,
In the step (A), the operation of suspending the dispersion processing is performed once or more for a total of 1 to 6000 minutes, and the suspension time of one time is 1 to 300 minutes.
Manufacturing method of solid electrolytic capacitors.

[2]
The method for producing a solid electrolytic capacitor according to the above [1], wherein seed particles protected and colloidalized by polyanions are dispersed in the aqueous medium.

[3]
The method for manufacturing a solid electrolytic capacitor according to the above [1] or [2], wherein the operation of suspending the dispersion processing is performed 2 to 20 times.

[4]
The method for manufacturing a solid electrolytic capacitor according to any one of [1] to [3], wherein the time for suspending the dispersion processing is 6 to 2250 minutes in total.

[5]
Production of the solid electrolytic capacitor according to any one of [1] to [4], wherein the viscosity of the dispersion liquid (1) after the suspension is 1.05 to 100.0 times the viscosity before the suspension. Method.

[6]
The method for producing a solid electrolytic capacitor according to any one of [1] to [5], wherein a salt compound is added to the dispersion liquid (1) in the step (A).

[7]
The method for producing a solid electrolytic capacitor according to any one of [2] to [6], wherein the seed particles are particles of a polymer of an ethylenically unsaturated monomer.

[8]
The method for producing a solid electrolytic capacitor according to any one of [1] to [7], wherein in the step (A), the dispersion treatment includes a dispersion treatment by ultrasonic irradiation.

[9]
The method for producing a solid electrolytic capacitor according to any one of [1] to [8], wherein the dispersion treatment in the step (A) includes a dispersion treatment by a high-voltage homogenizer.

[10]
The method for producing a solid electrolytic capacitor according to any one of [1] to [9] above, wherein the monomer compound is at least one selected from the group consisting of a pyrrole compound, an aniline compound, and a thiophene compound.

[11]
The monomer compound has the following formula (1).

（式中、Ｒ¹及びＲ²は、各々独立して水素原子、水酸基、置換基を有してもよい置換基以外の部分の炭素数が１〜１８のアルキル基、置換基を有してもよい置換基以外の部分の炭素数が１〜１８のアルコキシ基、若しくは置換基を有してもよい置換基以外の部分の炭素数が１〜１８のアルキルチオ基を表し、または
Ｒ¹及びＲ²は、Ｒ¹とＲ²とが互いに結合して、置換基を有してもよい置換基以外の部分の炭素数が３〜１０の脂環、置換基を有してもよい置換基以外の部分の炭素数が６〜１０の芳香環、置換基を有してもよい置換基以外の部分の炭素数が２〜１０の酸素原子含有複素環、置換基を有してもよい置換基以外の部分の炭素数が２〜１０のイオウ原子含有複素環、若しくは置換基を有してもよい置換基以外の部分の炭素数が２〜１０のイオウ原子及び酸素原子含有複素環を表す。）
で示される化合物である前記［１］〜［１０］のいずれかの固体電解コンデンサの製造方法。

(In the formula, R ¹ and R ² each have an alkyl group and a substituent having 1 to 18 carbon atoms in a portion other than the substituent which may independently have a hydrogen atom, a hydroxyl group and a substituent. It represents an alkoxy group having 1 to 18 carbon atoms in a portion other than the substituent, or an alkylthio group having 1 to 18 carbon atoms in the portion other than the substituent which may have a substituent, or R ¹ and R. ^{In 2} , R ¹ and R ² are bonded to each other, and the portion other than the substituent which may have a substituent is an alicyclic having 3 to 10 carbon atoms, other than the substituent which may have a substituent. Aromatic ring having 6 to 10 carbon atoms, an oxygen atom-containing heterocycle having 2 to 10 carbon atoms other than the substituent which may have a substituent, and a substituent which may have a substituent. It represents a sulfur atom-containing heterocycle having 2 to 10 carbon atoms in the portion other than the substituent, or a sulfur atom-containing heterocycle having 2 to 10 carbon atoms in the portion other than the substituent which may have a substituent. )
The method for producing a solid electrolytic capacitor according to any one of the above [1] to [10], which is a compound represented by.

[12]
The method for producing a solid electrolytic capacitor according to any one of [1] to [11], wherein the polyanion is a polymer having at least one of a group consisting of a sulfo group and a salt of a sulfo group.

[13]
Any of the above [1] to [12], wherein the polyanion is used in an amount such that the ratio of the anionic group in the polyanion is 0.25 to 30.00 mol with respect to 1 mol of the monomer compound. A method for manufacturing a solid electrolytic capacitor.

[14]
The method for producing a solid electrolytic capacitor according to any one of [1] to [13], wherein in the step (A), the polymerization is carried out using at least one oxidizing agent selected from peroxodisulfuric acid and a salt thereof.

[15]
A solid electrolytic capacitor obtained by the production method according to any one of [1] to [14].
[16]
A monomer compound for obtaining a conjugated conductive polymer is polymerized in a liquid containing a polyanion and an aqueous medium to obtain a dispersion liquid (1) containing the conjugated conductive polymer, and the dispersion liquid is obtained. It has a step (A) of subjecting (1) to a dispersion treatment to obtain a dispersion liquid (2) containing the conjugated conductive polymer.
In the step (A), the operation of suspending the dispersion treatment is performed once or more for a total of 1 to 6000 minutes, and the suspension time of each time is 1 to 300 minutes. Dispersion containing a conjugated conductive polymer Method for producing liquid (2).

According to the method for producing a solid electrolytic capacitor of the present invention, a solid electrolytic capacitor having a high capacitance expression rate (capacitance) and a low equivalent series resistance (ESR) can be produced.
The solid electrolytic capacitor of the present invention has a high capacitance expression rate (capacitance) and a low equivalent series resistance (ESR).
Further, according to the method for producing a dispersion liquid of the present invention, it contains a conjugated conductive polymer useful for producing a solid electrolytic capacitor having a high capacitance expression rate (capacitance) and a low equivalent series resistance (ESR). It is possible to produce a dispersion liquid to be used.

FIG. 1 shows an outline of the step (A) in Examples and the like.

The method for manufacturing a solid electrolytic capacitor of the present invention is
A method for manufacturing a solid electrolytic capacitor having a porous anode made of a valve acting metal having a dielectric film on its surface and a solid electrolyte layer provided on the surface of the dielectric film.
A monomer compound for obtaining a conjugated conductive polymer is polymerized in a liquid containing a polyanion and an aqueous medium to obtain a dispersion liquid (1) containing the conjugated conductive polymer, and the dispersion liquid is obtained. A step (A) of subjecting (1) to a dispersion treatment to obtain a dispersion liquid (2) containing the conjugated conductive polymer.
The step (B) of adhering the dispersion liquid (2) to a porous anode made of a valve acting metal having a dielectric film on the surface, and the aqueous dispersion liquid (2) adhering to the porous anode body. Step of removing the medium to form a solid electrolyte layer (C)
Have,
The step (A) is characterized in that the operation of suspending the dispersion processing is performed once or more for a total of 1 to 6000 minutes, and the stop time of each operation is 1 to 300 minutes. However, the stop time of each time may be the same or different from each other.

In the present specification, a polymer obtained by polymerizing a monomer compound for obtaining a conjugated conductive polymer alone, and a polymer obtained by copolymerizing a plurality of the above-mentioned monomer compounds. The polymers are collectively referred to as "conjugated conductive polymer".

In the present specification, particles in a state in which polyanions are coordinated on the surface of seed particles to form protective colloids are referred to as “seed particles protected colloidalized by polyanions”. The polyanion means a polymer having two or more anionic groups.
As used herein, "(meth) acrylic" means acrylic or methacrylic, and "(meth) acrylate" means acrylate or methacrylate.

<Step (A) of obtaining a dispersion liquid (2) containing a conjugated conductive polymer>
(Preparation of dispersion liquid (1) containing conjugated conductive polymer)
The step of obtaining the dispersion liquid (1) containing the conjugated conductive polymer is carried out by polymerizing the above-mentioned monomer compound in a liquid containing a polyanion and an aqueous medium. As a more specific embodiment of this liquid,
Examples include (i) a liquid containing a monomeric compound, a polyanion and an aqueous medium, and (ii) a liquid containing a monomeric compound, seed particles protected and colloidalized by the polyanion, and an aqueous medium. The liquid (ii) may further contain a polyanion (a polyanion added separately from the polyanion used for protective colloidalization of seed particles; hereinafter may be referred to as “free polyanion”).

The dispersion liquid (1) containing the conjugated conductive polymer is composed of a composite of the conjugated conductive polymer and a polyanion, and a composite of the conjugated conductive polymer and seed particles protected and colloidalized by the polyanion. A dispersion in which at least one selected complex is dispersed in an aqueous medium. In this step, it is considered that the polyanion is doped with the conjugated conductive polymer to form a complex.

[Polymer compound]
The monomer compound for inducing the constituent unit of the conjugated conductive polymer is a pyrrole compound (that is, pyrrole which may have a substituent) and an aniline compound (that is, an aniline which may have a substituent). , And one or more selected from thiophene compounds (ie, thiophene which may have a substituent). Examples of the substituent include an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 10 carbon atoms, a heteroaryl group having 5 to 10 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, and an alkylthio having 1 to 18 carbon atoms. Examples include groups, carboxy groups, hydroxyl groups, halogen atoms and cyano groups. The alkyl group, aryl group, heteroaryl group, alkoxy group and alkylthio group may be substituted with one or more selected from a carboxy group, a hydroxyl group, a halogen atom and a cyano group. Further, two or more of the substituents may be condensed to form a ring.

Specific examples of the above-mentioned monomer compound include the pyrrole compounds, pyrrole, N-methylpyrrole, 3-methylpyrrole, 3-ethylpyrrole, 3-n-propylpyrrole, 3-butylpyrrole, and 3-octylpyrrole. , 3-decylpyrrole, 3-dodecylpyrrole, 3,4-dimethylpyrrole, 3,4-dibutylpyrrole, 3-carboxypyrrole, 3-methyl-4-carboxypyrrole, 3-methyl-4-carboxyethylpyrrole, 3 -Methyl-4-carboxybutylpyrrole, 3-hydroxypyrrole, 3-methoxypyrrole, 3-ethoxypyrrole, 3-butoxypyrrole, 3-hexyloxypyrrole, 3-methyl-4-hexyloxypyrrole, 3-methyl-4 -Hexyloxypyrrole;
The aniline compounds, aniline, 2-methylaniline, 3-isobutylaniline, 2-aniline sulfonic acid, 3-aniline sulfonic acid;
The thiophene compounds, thiophene, 3-methylthiophene, 3-ethylthiophene, 3-propylthiophene, 3-butylthiophene, 3-hexylthiophene, 3-heptylthiophene, 3-octylthiophene, 3-decylthiophene, 3- Dodecylthiophene, 3-octadecylthiophene, 3-bromothiophene, 3-chlorothiophene, 3-iodothiophene, 3-cyanothiophene, 3-phenylthiophene, 3,4-dimethylthiophene, 3,4-dibutylthiophene, 3-hydroxy Thiophene, 3-methoxythiophene, 3-ethoxythiophene, 3-butoxythiophene, 3-hexyloxythiophene, 3-heptyloxythiophene, 3-octyloxythiophene, 3-decyloxythiophene, 3-dodecyloxythiophene, 3-octadecyl Oxythiophene, 3,4-dihydroxythiophene, 3,4-dimethoxythiophene, 3,4-diethoxythiophene, 3,4-dipropoxythiophene, 3,4-dibutoxythiophene, 3,4-dihexyloxythiophene, 3 , 4-diheptyloxythiophene, 3,4-dioctyloxythiophene, 3,4-didecyloxythiophene, 3,4-didodecyloxythiophene, 3,4-ethylenedioxythiophene, 3,4-propylene dioxy Thiophene, 3,4-butylenedioxythiophene, 3-methyl-4-methoxythiophene, 3-methyl-4-ethoxythiophene, 3-carboxythiophene, 3-methyl-4-carboxythiophene, 3-methyl-4-carboxy Ethylthiophene, 3-methyl-4-carboxybutylthiophene, 3,4-ethyleneoxythithiophene;
Can be mentioned.

The monomer compound may be used alone or in combination of two or more.
Among the above compounds, pyrrole, N-methylpyrrole, thiophene, 3-methylthiophene, 3-methoxythiophene and 3,4-ethylenedioxythiophene are preferable from the viewpoint of obtaining a conjugated conductive polymer having high conductivity. ..

Among the above compounds, the monomer compound preferably contains a compound represented by the following formula (1), more preferably contains a compound represented by the following formula (2), 3,4-. More preferably, it contains ethylenedioxythiophene.

In the above formula (1), R ¹ and R ² each independently have a hydrogen atom, a hydroxyl group, and a carbon number which may have a substituent (the carbon number of the substituent is not included. The same applies hereinafter. ) Represents an alkyl group of 1 to 18, an alkoxy group having 1 to 18 carbon atoms which may have a substituent, or an alkylthio group having 1 to 18 carbon atoms which may have a substituent. R ¹ and R ² are bonded to each other to form a ring, an alicyclic ring having 3 to 10 carbon atoms which may have a substituent, and an aromatic ring having 6 to 10 carbon atoms which may have a substituent. An oxygen atom-containing heterocycle having 2 to 10 carbon atoms which may have a substituent, a sulfur atom-containing heterocycle having 2 to 10 carbon atoms which may have a substituent, or a carbon which may have a substituent. It represents a heterocycle containing sulfur atoms and oxygen atoms of the number 2 to 10. "R ¹ and R ² were bonded to each other to form a ring" means that "R ¹ and R ² were bonded to each other to form a ring together with two carbon atoms in the thiophene skeleton of the formula (1)." The number of carbon atoms in the ring formed by bonding R ¹ and R ² to each other includes two carbon atoms in the thiophene skeleton.

Examples of the substituent include an aryl group having 6 to 10 carbon atoms, a heteroaryl group having 5 to 10 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an alkylthio group having 1 to 18 carbon atoms, a carboxy group, a hydroxyl group, and a halogen atom. And cyano groups. The alkyl group, aryl group, heteroaryl group, alkoxy group and alkylthio group may be substituted with a carboxy group, a hydroxyl group, a halogen atom or a cyano group. Further, two or more substituents may be condensed to form a ring.

Examples of the oxygen atom-containing heterocycle include an oxylan ring, an oxetane ring, a furan ring, a hydrofuran ring, a pyran ring, a pyrone ring, a dioxane ring, and a trioxane ring.
Examples of the sulfur atom-containing heterocycle include a thielan ring, a thietan ring, a thiophene ring, a thiane ring, a thiopyran ring, a thiopyrylium ring, a benzothiopyran ring, a dithiolane ring, a dithiolane ring, and a trithian ring.

Examples of the sulfur atom- and oxygen atom-containing heterocycles include an oxathiorane ring and an oxatian ring.
In formula (2), R ³ and R ⁴ each independently represent an alkyl group having 1 to 4 carbon atoms which may have a hydrogen atom or a substituent, or R ³ and R ⁴ are mutually exclusive. It represents an oxygen atom-containing heterocycle having 3 to 6 carbon atoms, which may have a substituent and is bonded to form a ring.

R ³ and R ⁴ are preferably oxygen atom-containing heterocycles having 3 to 6 carbon atoms which may have a substituent and which R ³ and R ⁴ are bonded to each other to form a ring. "R ³ and R ⁴ bonded to each other to form a ring" means that "R ³ and R ⁴ bonded to each other, two adjacent oxygen atoms, and 2 in the thiophene skeleton of formula (2)." It means that "a ring was formed with one carbon atom", and the carbon number of the ring formed by bonding R ³ and R ⁴ to each other includes two carbon atoms in the thiophene skeleton.

Examples of the oxygen atom-containing heterocycle include a dioxane ring, a trioxane ring, and the like, and a dioxane ring is preferable. Examples of the substituent include an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 10 carbon atoms, a heteroaryl group having 5 to 10 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, and an alkylthio having 1 to 18 carbon atoms. Examples include groups, carboxy groups, hydroxyl groups, halogen atoms and cyano groups. The alkyl group, aryl group, heteroaryl group, alkoxy group and alkylthio group may be substituted with a carboxy group, a hydroxyl group, a halogen atom or a cyano group. Further, two or more substituents may be condensed to form a ring.

[Conjugated conductive polymer]
The conjugated conductive polymer is not particularly limited as long as it is an organic polymer compound having a π-conjugated system in the main chain. As the conjugated conductive polymer, there are two types of monomer units of polypyrroles, polythiophenes, polyisothianaftens, polyacetylenes, polyphenylenes, polyphenylene vinylenes, polyanilines, polyacenes, polythiophene vinylenes, and polymers. Examples thereof include copolymers containing the above.

Among these conjugated conductive polymers, polypyrrole, poly (N-methylpyrrole), polythiophene, poly (3-methylthiophene), poly (3-methoxythiophene) and poly (3,) are high in conductivity. 4-ethylenedioxythiophene) is preferred. In particular, poly (3,4-ethylenedioxythiophene) (PEDOT) is more preferable because it has higher conductivity and excellent heat resistance.

[Polyanion]
The polyanion is a polymer having two or more monomer units having an anionic group, coordinates on the surface of seed particles to form a protective colloid, and functions as a dopant for a conjugated conductive polymer. ..

Examples of the anionic group include a sulfo group or a group consisting of a salt thereof (a group formed by substituting a hydrogen atom of a sulfo group with a metal atom or the like. For example, SO ₃ Na, SO ₃ K, SO ₃ (NH ₄ )). , A group consisting of a phosphoric acid group or a salt thereof (a group formed by substituting a hydrogen atom of a phosphoric acid group with a metal atom, etc. For example, PO ₄ Na ₂ , PO ₄ NaH, PO ₄ K ₂ , PO ₄ KH, PO ₄ ( NH ₄ ) ₂ , PO ₄ (NH ₄ ) H.), monosubstituted phosphate group, carboxyl group or a group consisting of a salt thereof (a group formed by substituting a hydrogen atom of a carboxyl group with a metal atom, for example, COONa, COOK, COO (NH ₄ ).), Monosubstituted sulfate group. Among these, a strongly acidic group is preferable, a group composed of a sulfo group or a salt thereof, a group composed of a phosphoric acid group or a salt thereof is more preferable, and a group composed of a sulfo group or a salt thereof is further preferable.

The anionic group may be directly attached to the main chain of the polymer or may be attached to the side chain. When the anionic group is attached to the side chain, the doping effect becomes more remarkable, so that it is preferably attached to the end of the side chain.

The polyanion may have a substituent and / or a bonded structure other than the anionic group. Examples of the substituent include an alkyl group, a hydroxyl group, an alkoxy group, a cyano group, a phenyl group, a hydroxyphenyl group, a halogeno group, an alkenyl group, an amino group, an oxycarbonyl group and a carbonyl group. Examples of the bond structure include an ester bond, an imide bond, and an amide bond. Among these, an alkyl group, a hydroxyl group, a cyano group, a hydroxyphenyl group and an oxycarbonyl group are preferable, and an alkyl group, a hydroxyl group and a cyano group are more preferable. The substituent and / or bond structure may be directly attached to the polymer main chain or may be attached to the side chain. When a substituent is attached to the side chain, the effect of each substituent is exhibited. Therefore, it is preferable that the substituent is attached to the end of the side chain.

Alkyl groups that can be substituted in polyanions can be expected to have an effect of increasing solubility and dispersibility in aqueous media, compatibility and dispersibility with conjugated conductive polymers, and the like. Alkyl groups include methyl group, ethyl group, propyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group and other chain alkyl groups; cyclopropyl group, Cycloalkyl groups such as cyclopentyl group and cyclohexyl group can be mentioned. Considering the solubility in an aqueous medium, the dispersibility in a conjugated conductive polymer, the steric hindrance, and the like, an alkyl group having 1 to 12 carbon atoms is more preferable.

Hydroxy groups that can be substituted in polyanions facilitate the formation of hydrogen bonds with other hydrogen atoms, etc., and enhance the solubility in aqueous media, compatibility with conjugated conductive polymers, dispersibility, and adhesiveness. Expected to work. The hydroxyl group is preferably bonded to the terminal of an alkyl group having 1 to 6 carbon atoms bonded to the polymer main chain.

The cyano group and hydroxyphenyl group that can be substituted in the polyanion can be expected to have an action of increasing compatibility with a conjugated conductive polymer, solubility in an aqueous medium, and heat resistance. The cyano group is directly bonded to the polymer main chain, bonded to the terminal of an alkyl group having 1 to 7 carbon atoms bonded to the polymer main chain, or the terminal of an alkenyl group having 2 to 7 carbon atoms bonded to the polymer main chain. It is preferably bound to. The hydroxyphenyl group is preferably a 4-hydroxyphenyl group.

The oxycarbonyl group that can be substituted in the polyanion is preferably an alkyloxycarbonyl group, an aryloxycarbonyl group, or an alkyloxycarbonyl group or an aryloxycarbonyl group that is directly bonded to the polymer main chain and is formed by interposing another functional group.

The composition of the polymer main chain of the polyanion is not particularly limited. Examples of the polymer main chain include polyalkylene, polyimide, polyamide, polyester and the like. Of these, polyalkylene is preferable from the viewpoint of synthesis and availability.

Polyalkylene is a polymer composed of repeating units of ethylenically unsaturated monomers. The polyalkylene may have a carbon-carbon double bond in the main chain. Examples of the polyalkylene include polyethylene, polypropylene, polybutene, polypentene, polyhexene, polyvinyl alcohol, polyvinylphenol, poly (3,3,3-trifluoropropylene), polyacrylonitrile, polyacrylate, polymethacrylate, polystyrene, polybutadiene, and poly. Isoprene and the like can be mentioned.

As the polyimide, pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, 2,2,3,3-tetracarboxydiphenylether dianhydride, 2,2- [4,4 '-Di (dicarboxyphenyloxy) phenyl] Examples thereof include those obtained by a polycondensation reaction between an acid anhydride such as propanedianhydride and a diamine such as oxydianiline, paraphenylenediamine, metaphenylenediamine and benzophenonediamine. ..

Examples of the polyamide include polyamide 6, polyamide 6, 6, polyamide 6, 10 and the like.
Examples of polyester include polyethylene terephthalate and polybutylene terephthalate.

Specific examples of a polymer having at least one of a sulfo group and a group consisting of a salt of the sulfo group, which are preferably used as polyanions, include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, ethyl sulfonic acid polyacrylate, and polyacrylic acid. Acids Butyl sulfonic acid, poly (2-acrylamide-2-methylpropane sulfonic acid), and polyisoprene sulfonic acid, and all or part of these sulfo groups replaced with groups consisting of salts of sulfo groups. Be done. These may be homopolymers or copolymers containing two or more kinds of monomer units. Of these, polystyrene sulfonic acid, polyisoprene sulfonic acid, ethyl sulfonic acid polyacrylate, butyl sulfonic acid polyacrylate, and all or part of these sulfo groups are salts of sulfo groups from the viewpoint of imparting conductivity. It is preferably replaced with a group consisting of a group consisting of, and more preferably a group consisting of a salt of a sulfo group in which all or part of the sulfo group of polystyrene sulfonic acid (PSS) and polystyrene sulfonic acid is replaced.

A polymer having at least one of a polyanion, particularly a group consisting of a sulfo group and a salt of a sulfo group, improves the dispersibility of the monomeric compound in an aqueous medium and further functions as a dopant for a conjugated conductive polymer.

The weight average molecular weight of the polyanion is preferably 1,000 to 1,000,000, more preferably 5,000 to 500,000, and even more preferably 50,000 to 300,000. When the weight average molecular weight is in this range, the solubility of the polyanion in the aqueous medium and the doping of the polyanion into the conjugated conductive polymer are good. The weight average molecular weight referred to here is a value measured as a polystyrene-equivalent molecular weight using gel permeation chromatography.

The polyanion may be a commercially available product having the above-mentioned characteristics, or may be synthesized by a known method. A method for synthesizing a polyanion is described in, for example, Japanese Patent Application Laid-Open No. 2005-76016.

The total amount of polyanions used, that is, those used for protective colloidalization of seed particles, those pre-prepared before the start of polymerization and those added during polymerization, is the total amount of polyanions used in the polyanions. However, the amount is preferably 0.25 to 30 mol, more preferably 0.5 to 28 mol, and further preferably 0.8 to 25 mol with respect to 1 mol of the monomer compound.

The amount of the polyanion used with respect to 100 parts by mass of the conjugated conductive polymer produced in this step is preferably 10 to 30,000 parts by mass, more preferably 30 to 20,000 parts by mass, and further preferably 50 to 50 parts by mass. It is 15,000 parts by mass.
When the amount of the polyanion used is 10 parts by mass or more, the conductivity of the conductive polymer is appropriate, and when it is 30,000 parts by mass or less, the dispersibility of the conductive polymer in an aqueous medium is good.

[Seed particles]
The seed particles that may be used in the present invention are polymer particles that are protected colloidalized with polyanions in an aqueous medium. As the seed particles, for example, those composed of a polymer containing one or more kinds of ethylenically unsaturated monomers as a constituent unit are preferable. The polymer may be one kind alone, a mixture of two or more kinds, and may be either crystalline or amorphous. In the case of crystallinity, the crystallinity is preferably 50% or less.

The crystallinity can be measured with a differential scanning calorimeter or an X-ray diffractometer.
The ethylenically unsaturated monomer is a monomer having one or more polymerizable ethylenically carbon-carbon double bonds. Examples of the ethylenically unsaturated monomer include (meth) acrylates having linear, branched or cyclic alkyl chains; aromatic vinyl compounds such as styrene and α-methylstyrene; heterocyclic compounds such as vinylpyrrolidone. Vinyl compounds; hydroxyalkyl (meth) acrylates; dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl acrylate; vinyl esters such as vinyl acetate and vinyl alkanoate; monoolefins such as ethylene, propylene, butylene and isobutylene; butadiene, isoprene , Coupling diolefins that may have halogen atoms such as chloroprene; α, β-unsaturated mono or dicarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid; acrylonitrile and the like. Vinyl cyanide compounds; examples thereof include carbonyl group-containing vinyl compounds such as acrylonitrile and diacetoneacrylamide. These ethylenically unsaturated monomers may be used alone or in combination of two or more.

The ethylenically unsaturated monomer may be a crosslinkable monomer, and is crosslinked with each other or in combination with a crosslinkable monomer and an ethylenically unsaturated compound having an active hydrogen group. May be good. By using a crosslinked copolymer, the water resistance, moisture resistance, heat resistance, etc. of the conductive film can be improved. The crosslinkable monomer is a compound having two or more ethylenic carbon-carbon double bonds, or one or more ethylenic carbon-carbon double bonds and one other reactive group. The compound having the above.

Examples of the crosslinkable monomer include epoxy group-containing α, β-ethylenically unsaturated compounds such as glycidyl (meth) acrylate; hydrolyzable alkoxysilyls such as vinyltriethoxysilane and γ-methacryloxypropyltrimethoxysilane. Group-containing α, β-ethylenically unsaturated compounds; polyfunctional vinyl compounds such as ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, divinylbenzene, diallyl phthalate and the like can be mentioned. ..

Further, using a crosslinkable monomer such as a carbonyl group-containing α, β-ethylenically unsaturated compound (containing a ketone group), a polyhydrazine compound (particularly, oxalic acid dihydrazide, succinate dihydrazide, adipic acid dihydrazide, etc. It may be crosslinked in combination with (having two or more hydrazide groups such as polyacrylic acid hydrazide).
The content of the crosslinkable monomer in the ethylenically unsaturated monomer is preferably 50% by mass or less, more preferably 35% by mass or less, still more preferably 25% by mass or less.

(Production of seed particles protected and colloidalized by polyanions)
Seed particles are protected colloidalized by polyanions in an aqueous medium. The dispersion of the protective colloidalized seed particles dispersed in the aqueous medium can be produced as a resin emulsion.

The polymerization reaction of the ethylenically unsaturated monomer in producing a resin emulsion is a radical polymerization reaction, which is a batch type, semi-continuous type, or continuous type using a normal pressure reactor or a pressure resistant reactor. It is done in. Further, from the viewpoint of reaction stability during polymerization and uniformity of the polymer, the ethylenically unsaturated monomer is dissolved, emulsified or dispersed in the aqueous medium in the polyanion-containing solution in which the polyanion is previously dissolved in the aqueous medium. It is preferable to polymerize the ethylenically unsaturated monomer by continuously or intermittently adding the prepared ethylenically unsaturated monomer solution.

The reaction temperature depends on the decomposition temperature of the polymerization initiator, but is usually 10 to 100 ° C, generally 30 to 90 ° C. The reaction time is not particularly limited, and may be appropriately adjusted according to the amount of each component used, the type of polymerization initiator, the reaction temperature, and the like.

During radical polymerization, polyanions, which are protective colloids, contribute to the stability of emulsion particles. If necessary, emulsifiers such as anionic emulsifiers, nonionic emulsifiers and reactive emulsifiers, and aliphatic amines can be added to the polymerization system. It may be added. The type and amount of the emulsifier and the aliphatic amine may be appropriately adjusted according to various conditions such as the amount of the polyanion used and the composition of the ethylenically unsaturated monomer.

Examples of the emulsifier used for such a radical polymerization reaction include alkyl sulfate ester salt, alkylbenzene sulfonate, alkyl sulfosuccinate, alkyl diphenyl ether disulfonate, polyoxyalkylene alkyl sulfate, and polyoxyalkylene alkyl phosphate. Examples thereof include anionic emulsifiers such as esters, and nonionic surfactants such as polyoxyalkylene alkyl ethers, polyoxyalkylene alkyl phenol ethers, polyoxyalkylene fatty acid esters, and polyoxyalkylene sorbitan fatty acid esters.

Examples of the aliphatic amine include primary amines such as octylamine, laurylamine, myristylamine, stearylamine and oleylamine, secondary amines such as dioctylamine, dilaurylamine, distearylamine and diorailamine, and N, N-dimethyllauryl. Amine, N, N-dimethylmyristylamine, N, N-dimethylpalmitylamine, N, N-dimethylstearylamine, N , N-dimethylbehenylamine, N, N-dimethyloleylamine, N-methyldidecylamine, N − Tertiary amines such as methyldiorail amines can be mentioned.
The emulsifier and the aliphatic amine may be used alone or in combination of two or more.

Further, when the above-mentioned polymerization reaction of the ethylenically unsaturated monomer is carried out within a range that does not impair the characteristics of the obtained conjugated conductive polymer, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, etc. are contained in the aqueous medium. A water-soluble polymer such as hydroxypropyl cellulose or polyvinylpyrrolidone may coexist.

Examples of the aqueous medium used in producing the dispersion of seed particles include water or a mixed solvent of water and a water-soluble solvent. The ratio of the water-soluble solvent in the mixed solvent is preferably 0 to 30% by mass. When the proportion of the water-soluble solvent is 30% by mass or less, the polymerization reaction of the resin emulsion can be stabilized. Examples of the water-soluble solvent include alcohols such as methanol, ethanol and isopropyl alcohol; ketones such as acetone; glycols such as ethylene glycol and propylene glycol; ethers such as ethylene glycol monomethyl ether and ethylene glycol monobutyl ether. ..

As the polymerization initiator used in the radical polymerization, known and commonly used ones can be used. Examples of the polymerization initiator include inorganic peroxides such as hydrogen peroxide, persulfate, ammonium persulfate, potassium persulfate, and sodium persulfate; and organic peroxides such as benzoyl peroxide and t-butyl hydroperoxide. Includes azo compounds such as 2,2'-azobisisobutyronitrile and 4,4'-azobis (4-cyanovaleric acid). Further, if necessary, these polymerization initiators may be combined with sodium sulfoxylate formaldehyde, ascorbic acids, sulfites, tartaric acid or salts thereof, iron (II) sulfate and the like for redox polymerization. Further, if necessary, a chain transfer agent such as alcohols and mercaptans may be used.

The amount of the ethylenically unsaturated monomer used in the production of the protective colloidalized seed particles is preferably 10 to 100 parts by mass, more preferably 20 to 80 parts by mass, still more preferably 100 parts by mass with respect to 100 parts by mass of the polyanion. Is 30 to 70 parts by mass. When the amount of the ethylenically unsaturated monomer used is 10 parts by mass or more, the proportion of the conductive polymer containing the seed particles protected and colloidalized by the polyanion in the conjugated conductive polymer is appropriate, and the polymerization is carried out. It is possible to suppress thickening due to. When it is 100 parts by mass or less, the stability of the protective colloidalized seed particles is good.

The particle size d50 (50% median diameter on a volume basis) of the seed particles that have been protected and colloidalized and dispersed in the aqueous medium is preferably 0.01 to 10 μm, more preferably 0.05. It is ~ 1 μm, more preferably 0.1 to 0.8 μm. The particle size distribution of the seed particles can be measured with a Microtrack UPA type particle size distribution measuring device manufactured by Nikkiso Co., Ltd. When the particle size d50 of the seed particles dispersed in the aqueous medium is 0.01 μm or more, the dispersibility of the seed particles is good, and when it is 10 μm or less, the particles are difficult to settle.

<< Polymerization of monomeric compounds >>
Polymerization of the monomeric compound is carried out in a liquid containing the monomeric compound, a polyanion and an aqueous medium. As a more specific embodiment of this liquid,
Examples thereof include (i) a liquid containing the monomer compound, the polyanion and an aqueous medium, and (ii) a liquid containing the seed particles and the aqueous medium protected and colloidalized by the monomer compound and the polyanion.

[Polymer compound solution]
In order to polymerize the monomer compound in the above liquid, a dispersion liquid containing the monomer compound and the polyanion, or a dispersion liquid containing the monomer compound and the seed particles protected and colloidalized by the polyanion (hereinafter referred to as At the same time, it may be simply referred to as "monomer compound solution").

The monomer compound solution may be any one in which the monomer compound is dissolved, emulsified or dispersed, and for that purpose, a powerful stirring device such as a homogenizer or an ultrasonic irradiation device is usually used. For example, in the case of emulsification by ultrasonic irradiation, the ultrasonic irradiation energy is not particularly limited as long as a uniform monomeric compound solution can be obtained. The ultrasonic irradiation is preferably performed with a power consumption of 5 to 500 W / L (liter) and an irradiation time of 0.1 to 2 hours / L (liter).

Further, when a dispersion containing the monomer compound and the seed particles protected and colloidalized by the polyanion is used as the monomer compound solution, from the viewpoint of suppressing the aggregation of the conjugated conductive polymer generated by the polymerization, from the viewpoint of suppressing the aggregation of the conjugated conductive polymer. It is preferred that the monomeric compound solution contain the same polyanions (ie, free polyanions) used for protective colloidalization of seed particles. This polyanion (ie, free polyanion) can be contained by adding to the monomeric compound solution and dissolving, emulsifying or dispersing. When the free polyanion is contained in the monomer compound solution, the amount thereof is 5 to 99% by mass of the total amount of the polyanion used (that is, the total amount of the polyanion and the free polyanion used for the protective colloidalization of the seed particles). Is preferable, 10 to 90% by mass is more preferable, and 20 to 80% by mass is further preferable.

[Aqueous medium]
The aqueous medium used for the polymerization of the monomer compound is a composite of a conjugated conductive polymer and seed particles protected and colloidalized by a polyanion, a composite of a conjugated conductive polymer and a polyanion, or two of these. It is not particularly limited as long as it can disperse the seed complex, but the same kind as the aqueous medium used for the dispersion liquid of the seed particles is preferable.

Examples of the aqueous medium used for the polymerization of the monomer compound include water or a mixed solvent of water and a water-soluble solvent.
Examples of the water-soluble solvent include amides such as N-vinylpyrrolidone, hexamethylphosphortriamide, N-vinylformamide and N-vinylacetamide; phenols such as cresol, phenol and xylenol; methanol, ethanol, isopropyl alcohol and the like. Monovalent alcohols; ethylene glycol, propylene glycol, dipropylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, diglycerin, isoprene glycol, butanediol, 1,5-pentanediol, 1,6- Polyhydric alcohols such as hexanediol, 1,9-nonanediol, neopentyl glycol; ketones such as acetone; carbonate compounds such as ethylene carbonate and propylene carbonate; dioxane, diethyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether , Polypropylene glycol dialkyl ethers, ethylene glycol monomethyl ethers, ethylene glycol monobutyl ethers and other ethers; heterocyclic compounds such as 3-methyl-2-oxazolidinone; acetonitrile, glutalogie nitriles, methoxy acetonitrile, propionitrile, benzonitrile and the like. Examples include nitriles. These solvents can be used alone or in combination of two or more.

The ratio of the water-soluble solvent in the aqueous medium is preferably 0 to 30% by mass. The aqueous medium more preferably contains 50% by mass or more of water, and further preferably uses water alone. When the proportion of the water-soluble solvent is 30% by mass or less, the polymerization reaction of the monomer compound can be stabilized.

The amount of the aqueous medium used is preferably 10 to 50,000 parts by mass with respect to a total of 100 parts by mass of the monomer compound, the seed particles protected and colloidalized by the polyanion, and the polyanion that does not contribute to the protective colloidalization. , More preferably 50 to 10,000 parts by mass. When the amount of the aqueous medium used is 10 parts by mass or more, the viscosity of the dispersion during polymerization is appropriate, and when it is 50,000 parts by mass or less, the performance of the solid electrolytic capacitor is good.

[Oxidant]
In the polymerization of the above-mentioned monomer compound, for example, in the case of producing a dispersion liquid containing polypyrroles and polythiophenes as a conjugated conductive polymer, the monomer compound liquid is brought to a predetermined temperature in the presence of an oxidizing agent. The polymerization is started by.

Examples of the oxidizing agent include peroxodisulfate such as peroxodisulfuric acid, ammonium peroxodisulfate, sodium peroxodisulfate and potassium peroxodisulfate; metal halogen compounds such as boron trifluoride; ferric chloride, ferric sulfate and chloride. Transition metal compounds such as cupric oxide; metal oxides such as silver oxide and cesium oxide; peroxides such as hydrogen peroxide and ozone; organic peroxides such as benzoyl peroxide; oxygen and the like. Of these, peroxodisulfate and peroxodisulfate are preferable, and peroxodisulfate is more preferable.
The above-mentioned oxidizing agents may be used alone or in combination of two or more.

[Polymerization temperature]
The temperature at the time of polymerization of the above-mentioned monomer compound is usually 5 to 80 ° C, preferably 10 to 60 ° C, and more preferably 15 to 40 ° C. When the temperature at the time of polymerization is within this range, the polymerization can be carried out at an appropriate reaction rate, the increase in the viscosity of the reaction solution can be suppressed, and the production of the dispersion liquid containing the conjugated conductive polymer is stable. It can be carried out in an economical time, and the conductivity of the obtained conjugated conductive polymer tends to be high. The temperature at the time of polymerization can be controlled by using a known heater or cooler. Further, if necessary, the polymerization may be carried out while changing the temperature within the above range.

[Addition of dispersion of protective colloidalized seed particles]
During the polymerization of the above-mentioned monomer compound using the dispersion liquid containing the above-mentioned monomer compound and the protective colloidalized seed particles, the dispersion liquid of the protective colloidalized seed particles by a polyanion is further added to the reaction solution. Is preferable. By further adding a predetermined amount of the dispersion liquid of the protective colloidalized seed particles during the polymerization of the above-mentioned monomer compound, the thickening of the reaction liquid at the time of polymerization can be suppressed, the stirring and mixing efficiency can be improved, and the production apparatus Load can be reduced. The amount of the dispersion liquid of the protective colloidalized seed particles added during the polymerization is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, based on the total amount of the dispersion liquid of the protective colloidalized seed particles to be used. , 30-70% by mass is more preferable.

[Addition of polyanion]
A polyanion may be further added to the reaction solution during the polymerization of the above-mentioned monomer compound. By further adding a part of a predetermined amount of polyanion during the polymerization of the above-mentioned monomer compound, the thickening of the reaction solution at the time of polymerization can be suppressed, the stirring and mixing efficiency can be improved, and the load on the manufacturing apparatus can be reduced. .. The amount of the polyanion added during the polymerization is preferably 0 to 90% by mass, more preferably 20 to 80% by mass, still more preferably 30 to 70% by mass, based on the total amount of the polyanion used.

(Preparation of dispersion liquid (2) containing conjugated conductive polymer)
In the step (A), the conjugated conductive polymer is obtained by preparing the dispersion (1) containing the conjugated conductive polymer as described above and subjecting the dispersion (1) to a dispersion treatment. A dispersion liquid (2) containing the mixture (hereinafter, also referred to as “conjugated conductive polymer-containing dispersion liquid (2)”) is obtained.

Two or more kinds of dispersion liquids (1) having different types of conjugated conductive polymers may be prepared, and the dispersion liquid obtained by mixing these may be subjected to a dispersion treatment.
The dispersion liquid (1) containing the conjugated conductive polymer was made into a protective colloid by (i) a composite of the conjugated conductive polymer and the polyanion, and (ii) the conjugated conductive polymer and the polyanion. At least one selected from the composite with the seed particles is a dispersion dispersed in an aqueous medium.

The complex may aggregate as the polymerization of the polymerizable compound progresses.
In order to improve the capacitance and ESR of the solid electrolytic capacitor (that is, to increase the capacitance of the solid electrolytic capacitor and reduce the ESR), it is necessary to improve the impregnation property into the porous anode. Therefore, in the present invention, the composite is crushed in the step (A) so that fine particles having an average particle size of 1 to 10 μm are dispersed.

[Distributed processing]
The dispersion treatment is for crushing the complex to the size of the fine particles, and is preferably performed by a powerful stirring device such as a homogenizer or ultrasonic irradiation. The dispersion treatment may be carried out when polymerizing the polymerizable compound. That is, the dispersion liquid (1) to be subjected to the dispersion treatment may contain the unreacted polymerizable compound. For example, Japanese Patent Application Laid-Open No. 2007-332183 describes a method of polymerizing a conjugated conductive polymer while stirring at a shear rate of 5,000 s- ¹ or higher.

In the case of ultrasonic irradiation, it is preferable to perform the power consumption per dispersion treatment liquid at 5 to 500 W / L. The distributed processing may be either a flow method or a batch method.
When a high pressure homogenizer is used, the pressure of the high pressure homogenizer is preferably 10 to 2000 bar, more preferably 20 to 1500 bar, still more preferably 50 to 1000 bar. When the pressure of the high-voltage homogenizer is 10 bar or more, the dispersion treatment is efficiently performed and the performance of the solid electrolytic capacitor is good. When the pressure of the high-pressure homogenizer is 2000 bar or less, the workability during the dispersion treatment is good.

For example, when a 1500 ml dispersion is dispersed using a high-pressure homogenizer having a dispersion processing capacity of 500 ml / min, the time required to disperse the entire amount of the dispersion once is 3 minutes. The dispersion treatment time is preferably a total of 15 to 900 minutes, more preferably 30 to 600 minutes, and even more preferably 60 to 300 minutes. When the dispersion treatment time of the high-voltage homogenizer is 15 minutes or more, the effect of the dispersion treatment is exhibited and the performance of the solid electrolytic capacitor is good. When the dispersion treatment time of the high-pressure homogenizer is 900 minutes or less, the efficiency of the dispersion treatment is good.

The total time for suspending the dispersion processing is 1 to 6000 minutes, more preferably 6 to 2250 minutes, and further preferably 20 to 750 minutes. If the total time for suspending the dispersion processing is 2 minutes or more, the performance of the solid electrolytic capacitor is good. If the time to suspend the distributed processing is 6000 minutes or less, the workability is good.

[Concentration of dispersion]
The concentration of the conjugated conductive polymer in the dispersion liquid (1) when the dispersion treatment is performed is not particularly limited as long as the productivity in the dispersion treatment is not impaired, but from the viewpoint of impregnation property into the solid electrolytic capacitor. The concentration of the finished product, that is, the concentration of the conjugated conductive polymer in the dispersion liquid (2) obtained in the step (A) is preferably 1.0 to 10.0% by mass. When it is 1.0% by mass or more, the ESR of the solid electrolytic capacitor is good (that is, the ESR can be made lower). When it is 10.0% by mass or less, the capacitance is good (that is, the capacitance can be made larger).

The concentration of the conjugated conductive polymer in the dispersion liquid (1) may be lowered by diluting with an aqueous medium. The timing of dilution may be before the dispersion treatment, during the dispersion treatment, or after the dispersion treatment, but it is preferably performed during the dispersion treatment. By diluting with an aqueous medium during the dispersion treatment, the dispersion treatment can be efficiently performed at a high concentration, and the influence of reaggregation due to the dilution can be reduced.

<Pause of distributed processing>
In the step (A), the operation of suspending the dispersion processing is performed once or more, for a total of 1 to 6000 minutes.

[Pause distributed processing]
By temporarily stopping the dispersion treatment and allowing the dispersion liquid (1) to stand, the dispersed complex and / or its crushed material (hereinafter, also referred to as “complex or the like”) is aggregated and aggregated. The dispersion liquid (1) thickens. By performing the dispersion treatment again after thickening, deagglomeration of the complex and the like can be promoted.

The details of the reason why the capacitance and ESR of the solid electrolytic capacitor are improved by promoting the deagglomeration of the composite or the like (that is, the reason why the capacitance is increased and the ESR is reduced) are unknown, but the surface of the composite or the like is unknown. It is presumed that the abundance of the conjugated conductive polymer in the above will change.

The operation of suspending the distributed processing may be performed once or a plurality of times. It is preferably 2 to 20 times, more preferably 3 to 15 times, still more preferably 4 to 10 times.
The pause time per pause is preferably 1 to 300 minutes, more preferably 2 to 150 minutes, and even more preferably 5 to 75 minutes. If the time for suspending the dispersion processing is 1 minute or more, the dispersion processing is efficiently performed, and a solid electrolytic capacitor having good performance is manufactured.

If the time for temporarily stopping the distributed processing is 300 minutes or less, the workability during the distributed processing is good.
The viscosity of the thickened dispersion (for example, the viscosity at the end of the pause) is preferably 1.05 to 100.0 times the viscosity before the thickening (for example, the viscosity at the start of the pause). It is more preferably 1.10 to 50.0 times the viscosity, more preferably 1.50 to 50.0 times the viscosity, and particularly preferably 3.00 to 50.0 times the viscosity. The upper limit may be, for example, 15 times. If the viscosity of the dispersion after thickening is 1.05 times or more the viscosity before thickening, the conjugated conductive polymer is efficiently deagglomerated and the performance of the solid electrolytic capacitor is good. .. When the viscosity of the dispersion liquid after thickening is 100.0 times or less the viscosity before thickening, the efficiency of the dispersion treatment is good.

[Addition of salt compounds]
In step (A), the salt compound can also be added to the aqueous medium. By adding the salt compound, the ionic strength of the dispersion liquid can be increased, the dispersed complex can be aggregated, and the dispersion liquid (1) can be further thickened.

The timing of adding the salt compound is not particularly limited, but in order to ensure uniformity, it is preferable during stirring in the polymerization of the monomer compound or during the dispersion treatment of the dispersion liquid (1). When desalting, which will be described later, may be carried out, a salt compound may be added again and dispersed after desalting. It is preferable to add the salt compound during the dispersion treatment of the dispersion liquid (1), and it is more preferable to add the salt compound 10 minutes before the end of the dispersion treatment.

The salt compound is not particularly limited as long as it dissolves in an aqueous medium, increases the ionic strength of the dispersion, and thickens the dispersion.
For example, it is preferably at least one salt compound selected from inorganic salts and organic salts that dissolve in an aqueous medium, increase the ionic strength of the dispersion, and thicken the dispersion.

Examples of the organic salt include citrate, lactate, glycolate, gluconate, acetate, propionate, fumarate, oxalate and tartrate salt, and more specifically, calcium acetate. , Magnesium acetate and the like, but are not limited thereto.

Examples of the inorganic salt include hydrochloride, carbonate, bicarbonate, sulfate, hydrogen phosphate, phosphate and the like, and more specifically, aluminum chloride, sodium nitrate, magnesium sulfate, aluminum sulfate, ammonium sulfate and the like. , Potassium sulfate, sodium sulfate and the like, but are not limited thereto. One of these salt compounds may be used alone, or two or more thereof may be used in combination.

The addition amount is preferably 0.01 to 30% by mass, more preferably 0.01 to 15% by mass, and 0.01 to 5% with respect to the total amount (100% by mass) of the dispersion liquid (2). The amount to be mass% is more preferable. When the addition amount is 0.01% by mass or more, the thickening of the dispersion liquid (1) is sufficient, and when it is 30% by mass or less, the efficiency of the dispersion treatment is good.

[Additive]
Various additives can be added to the dispersion liquid (1) containing the conjugated conductive polymer, if necessary. The additive is not particularly limited as long as it can be mixed with the conjugated conductive polymer and the seed particles or the polyanion protected and colloidalized by the polyanion.

Examples of such additives include neutralizing agents, water-soluble polymer compounds, water-dispersible compounds, alkaline compounds, surfactants, defoaming agents, coupling agents, antioxidants, and electrical conductivity improvers. Can be mentioned. These additives can be used alone or in combination of two or more.

A water-soluble polymer compound is a water-soluble polymer having a cationic group or a nonionic group in the main chain or side chain of the polymer. Specific examples of the water-soluble polymer compound include polyoxyalkylene, water-soluble polyurethane, water-soluble polyester, water-soluble polyamide, water-soluble polyimide, water-soluble polyacrylic, water-soluble polyacrylamide, polyvinyl alcohol, and polyacrylic acid. .. Of these, polyoxyalkylene is preferable.

Specific examples of the polyoxyalkylene include diethylene glycol, triethylene glycol, oligopolyethylene glycol, triethylene glycol monochlorohydrin, diethylene glycol monochlorohydrin, oligoethylene glycol monochlorohydrin, triethylene glycol monobromhydrin, diethylene glycol monobromhydrin, and the like. Oligoethylene glycol monobromhydrin, polyethylene glycol, glycidyl ethers, polyethylene glycol glycidyl ethers, polyethylene oxide, triethylene glycol / dimethyl ether, tetraethylene glycol / dimethyl ether, diethylene glycol / dimethyl ether, diethylene glycol / diethyl ether / diethylene glycol / dibutyl ether, di Examples thereof include propylene glycol, tripropylene glycol, polypropylene glycol, polypropylene dioxide, polyoxyethylene alkyl ether, polyoxyethylene glycerin fatty acid ester, and polyoxyethylene fatty acid amide.

The water-dispersible compound is a compound in which a part of a compound having a low hydrophilicity is replaced with a functional group having a high hydrophilicity, or a compound in which a compound having a high hydrophilicity group is adsorbed around a compound having a low hydrophilicity. Examples thereof include those (for example, emulsions) that are dispersed in water without being precipitated. Specific examples include polyester, polyurethane, acrylic resin, silicone resin, and emulsions of these polymers. Further, block copolymers and graft copolymers of acrylic resin and other copolymers such as polyester and polyurethane can be mentioned.

The water-soluble polymer compound and the water-dispersible compound may be used alone or in combination of two or more. By adding the water-soluble polymer compound and the water-dispersible compound, the viscosity of the dispersion liquid containing the conductive polymer can be adjusted, and the coating performance can be improved.

The amount of the water-soluble polymer compound and the water-dispersible compound used is preferably 100 to 100,000 parts by mass with respect to 100 parts by mass in total of the conjugated conductive polymer and the seed particles protected and colloidalized by the polyanion. , More preferably 25 to 50,000 parts by mass, still more preferably 50 to 20,000 parts by mass. When the amount of the water-soluble polymer compound and the water-dispersible compound is in the range of 10 to 100,000 parts by mass, appropriate conductivity can be exhibited and the equivalent series resistance (ESR) of a good solid electrolytic capacitor can be obtained. (That is, ESR can be reduced).

As the alkaline compound, a known inorganic alkaline compound or organic alkaline compound can be used. Examples of the inorganic alkaline compound include ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, and ammonia. Examples of the organic alkaline compound include aromatic amines, aliphatic amines, and alkali metal alkoxides. Corrosion resistance can be imparted to the article to which the dispersion has been applied by adding an alkaline compound, and the pH of the conjugated conductive polymer-containing dispersion can be adjusted.

Among aromatic amines, nitrogen-containing heteroaryl ring compounds are preferred. The nitrogen-containing heteroaryl ring compound is a nitrogen-containing heterocyclic compound exhibiting aromaticity. In aromatic amines, the nitrogen atom contained in the heterocycle has a conjugated relationship with other atoms.

Examples of the nitrogen-containing heteroaryl ring compound include pyridines, imidazoles, pyrimidines, pyrazines, and triazines. Among these, pyridines, imidazoles, and pyrimidines are preferable from the viewpoint of solvent solubility and the like.

Examples of the aliphatic amine include ethylmorpholine, ethylamine, n-octylamine, diethylamine, diisobutylamine, methylethylamine, trimethylamine, triethylamine, allylamine, 2-ethylaminoethanol, 2,2'-iminodiethanol, and N-ethylethylenediamine. Can be mentioned.

Examples of the alkali metal alkoxide include sodium alkoxides such as sodium methoxide and sodium ethoxide, potassium alkoxides, and calcium alkoxides.

Examples of the surfactant include anionic surfactants such as carboxylate, sulfonate, sulfate ester salt and phosphoric acid ester salt; cationic surfactants such as amine salt and quaternary ammonium salt; carboxybetaine and amino. Amphoteric surfactants such as carboxylates and imidazolium betaine; nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene glycerin fatty acid esters, ethylene glycol fatty acid esters and polyoxyethylene fatty acid amides.

Examples of the defoaming agent include silicone resin, polydimethylsiloxane, and silicone resin.
Examples of the antioxidant include phenol-based antioxidants, amine-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, sugars, and vitamins.

The electric conductivity improving agent is not particularly limited as long as it increases the electric conductivity of the dispersion liquid containing the conductive polymer. Examples of the electric conductivity improver include compounds containing an ether bond such as tetrahydrofuran; compounds containing a lactone group such as γ-butyrolactone and γ-valerolactone; caprolactam, N-methylcaprolactam, N, N-dimethylacetamide, and N. -Methylacetamide, N, N-dimethylformamide, N-methylformamide, N-methylformanilide, N-methylpyrrolidone, N-octylpyrrolidone, pyrrolidone and other compounds containing amides or lactam groups; tetramethylenesulfone, dimethylsulfoxide, etc. Sulfone compounds or sulfoxide compounds; saccharides or saccharide derivatives such as sucrose, glucose, fructose, lactos; sugar alcohols such as sorbitol, mannitol; imides such as succinimide, maleimide; 2-furancarboxylic acid, 3-furancarboxylic acid, etc. Fran derivatives; examples thereof include dialcohols or polyalcohols such as ethylene glycol, propylene glycol, glycerin, diethylene glycol and triethylene glycol. Among these, tetrahydrofuran, N-methylformamide, N-methylpyrrolidone, ethylene glycol, propylene glycol, glycerin, dimethyl sulfoxide, and sorbitol are preferable from the viewpoint of improving electrical conductivity, and among them, ethylene glycol, diethylene glycol, triethylene glycol, and propylene are preferable. Glycol and glycerin are more preferred. The electric conductivity improver may be used alone or in combination of two or more.

[Desalting]
When the dispersion liquid (1) contains a salt, the dispersion liquid (1) may be desalted after the dispersion treatment is completed. The composite of the conjugated conductive polymer and the polyanion dispersed up to the primary particles in the step (A) can maintain the dispersibility even if it is allowed to stand by desalting.
The desalting method is not particularly limited, and desalting can be performed by a dialysis method, a centrifugal washing method, an ion exchange method, or the like.

<Step (B) of Adhering Conjugated Conductive Polymer-Containing Dispersion Liquid (2) to Porous Anode
In the method for producing a solid electrolytic capacitor of the present invention, the conjugated conductive polymer-containing dispersion liquid (2) obtained in the above-mentioned step (A) is subjected to an anode made of a valve metal and at least one of the surface of the anode. It has a step (B) of adhering to the surface of a porous anode having a dielectric film formed on the portion.

The solid electrolytic capacitor according to the manufacturing method of the present invention may have, for example, a porous electrode made by sintering a valve metal powder having a high surface area, or a porous film obtained by etching a valve metal foil as an electrode. it can.

Examples of the valve metal include aluminum (Al), beryllium (Be), bismuth (Bi), magnesium (Mg), germanium (Ge), hafnium (Hf), niobium (Nb), antimony (Sb), and silicon (Si). , Tin (Sn), tantalum (Ta), titanium (Ti), vanadium (V), tungsten (W) and zirconium (Zr), and alloys or compounds of at least one of these metals with other elements. .. Of these, an electrode material composed of a valve metal of Al, Nb, or Ta is preferable.
A porous electrode made of a valve metal, for example, forms a dielectric oxide film on the surface by anodizing to form a porous anode.

The porous electrode is anodized by applying a voltage in a phosphoric acid solution, for example, and a dielectric oxide film can be formed on the surface of the porous electrode. The magnitude of the chemical conversion voltage can be determined by the thickness of the dielectric oxide film and the withstand voltage of the capacitor. The preferred chemical conversion voltage is 1 to 800 V, more preferably 1 to 300 V.

Next, the conjugated conductive polymer-containing dispersion (2) is attached to the porous anode. Examples of the method of adhering include known methods such as coating, spraying, and dipping. Above all, the immersion method is preferable because the conjugated conductive polymer-containing dispersion liquid (2) can be evenly and uniformly adhered to and permeated into the porous anode body. Further, the conjugated conductive polymer-containing dispersion liquid (2) may be impregnated under reduced pressure in order to impregnate the details of the porous anode.
The immersion time is usually 10 seconds to 5 minutes, and the temperature of the conjugated conductive polymer-containing dispersion (2) is usually 10 to 35 ° C., although it depends on the type of the aqueous medium.

<Step of forming a solid electrolyte layer (C)>
In the method for producing a solid electrolytic capacitor of the present invention, the aqueous medium is removed from the conjugated conductive polymer-containing dispersion liquid (2) attached to the porous anode obtained in the above step (B), and the solid electrolyte layer is used. It has a step (C) of forming. The removal of the aqueous medium in this step (C) does not mean that all of the aqueous medium is removed, and a part of the aqueous medium may remain as long as it does not affect the production of the solid electrolytic capacitor.

As a method for removing the aqueous medium, drying by heat treatment is preferable from the viewpoint of efficiency. The heating conditions can be determined in consideration of the boiling point and volatility of the aqueous medium. The heating is preferably carried out in a temperature range in which the conductive polymer is not deteriorated by oxygen, for example, 10 to 300 ° C., preferably 50 to 200 ° C. The heat treatment time is preferably 5 seconds to several hours. The heat treatment may be performed, for example, in the atmosphere using a hot plate, an oven, or a hot air dryer, or under reduced pressure for rapid heat treatment.

In the present invention, the step (B) for adhering the above-mentioned conjugated conductive polymer-containing dispersion (2) and the step (C) for forming the solid electrolyte layer are performed once or twice depending on the type of the electrode body. The above may be repeated. However, in the second and subsequent steps (B), the dispersion liquid (2) is adhered to the surface of the solid electrolyte layer formed in the step (C). The heat treatment may be performed each time the dispersion liquid is adhered to remove a part or all of the aqueous medium, or the dispersion liquid may be continuously adhered a plurality of times and finally the aqueous medium may be removed. Further, any electrolytic solution may be impregnated after removing a part or all of the aqueous medium contained in the adhered dispersion.

Through the above steps (A) to (C), a solid having a porous anode made of a valve acting metal having a dielectric film on its surface and a solid electrolyte layer provided on the surface of the dielectric film. Electrolytic capacitors are manufactured.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these examples. The methods for measuring the physical properties of the dispersions in Examples and Comparative Examples are as follows.

(1) Solid content concentration For the solid content concentration of each example, 10 g of the sample obtained in each example was used as an infrared moisture meter (manufactured by Kett Science Institute Headquarters, Inc., type FD-720, heating condition 110 ° C./30 minutes). The evaporation residue was calculated as a solid content.

(2) pH
The pH of the dispersion obtained in each example was measured at 25 ° C. using a pH meter (manufactured by DKK-TOA CORPORATION, model HM-30G).

(3) Viscosity The viscosity of the dispersion obtained in each example was measured at 23 ° C. and 60 rpm using a rotational viscometer (manufactured by Toki Sangyo Co., Ltd., model TV25 type viscometer).

(4) Particle size of seed particles The particle size of seed particles (including the thickness of the polyanion layer) was measured by a Microtrac UPA type particle size distribution measuring device manufactured by Nikkiso Co., Ltd.

(5) Weight average molecular weight of sodium polystyrene sulfonate The weight average molecular weight was measured by gel permeation chromatography. "Shodex (registered trademark) GPC 101" (column OHPak SB-806M HQ) manufactured by Showa Denko KK was used for the measurement, and the measurement conditions were a column temperature of 40 ° C., an eluate of water, and an elution rate of 1 ml / min. .. The weight average molecular weight was expressed in standard polystyrene equivalent molecular weight (Mw).

(6) Capacitance and Equivalent Series Resistance of Solid Electrolytic Capacitor Element The capacitance (μF) of the solid electrolytic capacitor element at 120 Hz and the equivalent series resistance [ESR] (mΩ) at 100 kHz are measured by an LCR meter (manufactured by Agilent). It was measured using model E4980A).

[Example 1]
(Preparation of dispersion of seed particles protected and colloidalized with polyanion)
86 g of styrene, 49 g of 2-ethylhexyl acrylate, 15 g of divinylbenzene and 500 g of a 22 mass% aqueous solution of sodium polystyrene sulfonate (Polynas PS-5, weight average molecular weight: about 120,000) manufactured by Tosoh Organic Chemical Co., Ltd. are stirred and mixed, and ethylene is mixed. A sex-unsaturated monomer mixture was prepared. On the other hand, 1000 g of a 22 mass% aqueous solution of sodium polystyrene sulfonate (same as above) was heated to 80 ° C. with stirring, and 2 g of potassium persulfate was added thereto. To the solution thus obtained, 40 g of the ethylenically unsaturated monomer mixed solution and a 2.5 mass% aqueous solution of potassium persulfate were added dropwise over 2 hours and 2.5 hours, respectively. After completion of the dropping, the reaction solution was held at 80 ° C. for 2 hours, and then cooled to room temperature (25 ° C.). To the obtained reaction solution, 1500 ml of a cation exchange resin (IR120B-H manufactured by Organo Corporation) and 1500 ml of an anion exchange resin (IRA410-OH manufactured by Organo Corporation) were added, and the mixture was stirred for 12 hours and then the ion exchange resin. I broke up. Ion-exchanged water (hereinafter, simply referred to as water) is added to the filtrate to adjust the solid content concentration to 15.0% by mass, and seed particles protected and colloidalized with polyanions (particle size d50: 0). A dispersion of .46 μm) was obtained.

(Step (A): Production of Dispersion Liquid (1) of Conjugated Conductive Polymer by Polymerization)
In a polyethylene container, 223.2 parts by mass of water, 31.5 parts by mass of a 12% by mass aqueous solution of sodium polystyrene sulfonate (same as above), and a dispersion of seed particles protected and colloidalized with the polyanion prepared as described above 34. 0 parts by mass was stirred and mixed at 32 ° C. To this mixed solution, 2.80 parts by mass of 3,4-ethylenedioxythiophene was added at 32 ° C., and the mixture was emulsified and mixed with a homomixer (Robomix manufactured by Tokushu Kika Kogyo Co., Ltd .; 4000 rpm) for 30 minutes. A quantitative compound dispersion was prepared. The amount of the sulfo group and the group consisting of the salt of the sulfo group per 1 mol of 3,4-ethylenedioxythiophene was 1.9 mol. The sulfo groups and the like are derived from a 12% by mass aqueous solution of sodium polystyrene sulfonate and sodium polystyrene sulfonate in the dispersion.

291.5 parts by mass of the monomer compound dispersion was put into a stainless steel container to which a high-share mixer (manufactured by Pacific Kiko Co., Ltd., Milder (registered trademark) 303V; 5000 rpm) and a circulation pump were connected, and the stirring blade and the stirring blade were charged. Stir with a high-share mixer while circulating at 32 ° C., and add 5.89 parts by mass of sodium peroxodisulfate and 6.88 parts by mass of a 1% by mass aqueous solution of iron (III) sulfate hexahydrate as an oxidizing agent to the dispersion. Was added and the polymerization reaction was carried out for 24 hours to obtain a dispersion liquid (1-1) containing a conjugated conductive polymer. The amount of the polyanion used with respect to 100 parts by mass of the conjugated conductive polymer was 261 parts by mass.

(Step (A): Production of Dispersion Liquid (2) of Conjugated Conductive Polymer by Dispersion Treatment)
Pure water was added to the dispersion liquid (1-1) having a solid content concentration of 5.80% by mass to adjust the solid content concentration to 4.73% by mass and the total volume to 1500 mL. After that, the dispersion liquid (1-1) (hereinafter, the dispersion liquid (1-1)) and those subjected to various operations (addition of pure water, high-pressure dispersion treatment, ion exchange, etc.) are not distinguished. The dispersion pressure described as "dispersion liquid (1-1)" (however, excluding the dispersion liquid (2-1) which is the final product) is dispersed by a high-pressure homogenizer (TWIN PANDA 600, manufactured by Niro Soavi). Was 400 bar, and high-pressure dispersion treatment was performed for a total of 45 minutes. In this high-pressure dispersion treatment, a 9-minute high-pressure dispersion treatment and a 10-minute pause were repeated four times, and finally a 9-minute high-pressure dispersion treatment was performed. The viscosity of the dispersion liquid (1-1) at the start of the final pause is 900 mPa · s, and the viscosity of the dispersion liquid (1-1) at the end of the final pause is 4500 mPa · s. It was 0 times. After that, pure water was added to adjust the dispersion liquid (1-1) to a solid content concentration of 3.99% by mass and a total volume of 1500 mL, and the dispersion liquid (1-1) was again subjected to a high-pressure homogenizer at 400 bar without pausing. High-pressure dispersion treatment was carried out for 135 minutes, and immediately after that, ions were exchanged with 100.5 g of a cation exchange resin and 87.9 g of an anion exchange resin for 3 hours for desalting. Then, the dispersion liquid (1-1) is filtered through a filter having a pore size of 5 μm, further filtered through a filter having a pore size of 3 μm, and pure water is added to adjust the solid content concentration to 1.60% by mass to adjust the pH to 1. A dispersion liquid (2-1) of a conjugated conductive polymer of 9. was obtained.
The outline of the step (A) is shown in FIG.

(Formation of a porous anode having a dielectric oxide film on its surface)
A porous anode having a dielectric oxide film on its surface, which is used for a solid electrolytic capacitor, was produced by the method described in JP-A-2011-77257. That is, using niobium powder for a capacitor, a porous anode body with an anode lead having a dielectric oxide film having niobium pentoxide formed on the surface of the anode body was produced. The capacitance of this porous anode in 20% by mass sulfuric acid was 21.4 μF.

(Steps (B) and (C): Fabrication of solid electrolytic capacitor)
After impregnating the porous anode obtained by the above method with the dispersion liquid (2-1) of the conjugated conductive polymer for 1 minute in the atmosphere of 25 ° C., a hot air dryer (manufactured by TABAI, type) It was dried at 120 ° C. for 30 minutes by ST-110). This process was repeated 10 times to form a solid electrolyte layer on the surface of the dielectric oxide film of the porous anode to obtain a solid electrolytic capacitor.

Next, the solid electrolytic capacitor was coated with a carbon paste so as not to come into contact with the anode lead terminals and dried, and further, a silver paste was applied to make contact between the anode and the cathode and dried on the lead frame. The anode lead wire was electrically connected to the anode lead portion of the lead frame and sealed with a resin to obtain a solid electrolytic capacitor element.

[Example 2]
A solid electrolytic capacitor element was manufactured in the same manner as in Example 1 except that the pause time was changed to 30 minutes for each pause.

[Example 3]
In the high-voltage dispersion treatment for 45 minutes, the solid electrolytic capacitor was repeated 7 times for 6 minutes and paused for 10 minutes, and finally the high-voltage dispersion treatment for 3 minutes was performed in the same manner as in Example 1. Manufactured the element.

[Example 4]
(Step (B): Production of Dispersion Liquid (1) Containing Conjugated Conductive Polymer (Does Not Contain Seed Particles))
In a polyethylene container, 231.0 parts by mass of water and 60.0 parts by mass of a 12% by mass aqueous solution of sodium polystyrene sulfonate were stirred and mixed at 32 ° C. To this mixed solution, 2.80 parts by mass of 3,4-ethylenedioxythiophene was added at 32 ° C., and the mixture was emulsified and mixed with a homomixer (Robomix manufactured by Tokushu Kika Kogyo Co., Ltd .; 4000 rpm) for 30 minutes. A quantitative compound dispersion was prepared.

293.8 parts by mass of the monomer compound dispersion was put into a stainless steel container to which a high-share mixer (manufactured by Pacific Kiko Co., Ltd., Milder (registered trademark) 303V; 5000 rpm) and a circulation pump were connected, and the stirring blade and Stir while circulating at 32 ° C. with a high-share mixer, and add 5.89 parts by mass of sodium peroxodisulfate and 6.88 parts by mass of a 1% by mass aqueous solution of iron (III) sulfate hexahydrate as an oxidizing agent. , A dispersion liquid (1-4) containing a conjugated conductive polymer was obtained by carrying out a polymerization reaction for 24 hours.
A solid electrolytic capacitor element was manufactured in the same manner as in Example 1 except that the dispersion liquid (1-1) was changed to the dispersion liquid (1-4).

[Example 5]
A solid electrolytic capacitor element was obtained in the same manner as in Example 1 except that the high-voltage dispersion treatment by the high-voltage homogenizer was changed to the dispersion treatment by the ultrasonic homogenizer. The power consumption of the ultrasonic homogenizer was 100 W / L (liter), and the irradiation time was 1 hour / L (liter).

[Example 6]
A solid electrolytic capacitor element was manufactured in the same manner as in Example 1 except that the dispersion pressure in the high-voltage dispersion treatment was changed to 250 bar.

[Example 7]
A solid electrolytic capacitor element was manufactured in the same manner as in Example 1 except that ammonium sulfate was added as a salt compound to the dispersion liquid (1-1) immediately before the high-pressure dispersion treatment.

[Example 8]
Conjugated system Conjugated system by adding ethylene glycol as an electric conductivity improver to the dispersion liquid (2-1) of the conjugated conductive polymer at a ratio of 5 parts by mass with respect to 95 parts by mass of the dispersion liquid (2-1). A solid electrolytic capacitor element was manufactured in the same manner as in Example 1 except that the dispersion liquid (2-8) of the conductive polymer was obtained.

[Comparative Example 1]
A solid electrolytic capacitor element was manufactured in the same manner as in Example 1 except that the suspension was not performed in the high-voltage dispersion treatment. The viscosity of the dispersion was measured 36 minutes after the start of the high-pressure dispersion treatment.

[Comparative Example 2]
A solid electrolytic capacitor element was manufactured in the same manner as in Example 4 except that the suspension was not performed in the high-voltage dispersion treatment. The viscosity of the dispersion was measured 36 minutes after the start of the high-pressure dispersion treatment.

[Comparative Example 3]
A solid electrolytic capacitor element was manufactured in the same manner as in Example 5 except that the suspension was not performed in the dispersion treatment. The viscosity of the dispersion was measured 36 minutes after the start of the high-pressure dispersion treatment.

[Comparative Example 4]
A solid electrolytic capacitor element was manufactured in the same manner as in Example 6 except that the suspension was not performed in the dispersion treatment. The viscosity of the dispersion was measured 36 minutes after the start of the high-pressure dispersion treatment.
Table 1 shows the manufacturing conditions and evaluation results (capacitance and equivalent series resistance) of Examples 1 to 8 and Comparative Examples 1 to 4.

From the results in Table 1, the solid electrolytic capacitors of Examples 1 to 8 using the dispersion liquid (2) of the conjugated conductive polymer in the step of adhering to the porous anode made of the valve acting metal having a dielectric coating. The element has a higher capacitance expression rate (capacitance) than the solid electrolytic capacitor elements of Comparative Examples 1 to 4 using the dispersion liquid which was not thickened by suspending the dispersion treatment in the step (A). It can be seen that the equivalent series resistance (ESR) is low.

In the present invention, since the dispersion liquid (1) containing the polyanion and the conjugated conductive polymer is dispersed, the solid electrolyte layer formed by removing the aqueous medium from the dispersion liquid (2), and It is impractical to show all possible structures of solid electrolytic capacitors.

Claims (15)

A method for manufacturing a solid electrolytic capacitor having a porous anode made of a valve acting metal having a dielectric film on its surface and a solid electrolyte layer provided on the surface of the dielectric film.
A monomer compound for obtaining a conjugated conductive polymer is polymerized in a liquid containing a polyanion and an aqueous medium to obtain a dispersion liquid (1) containing the conjugated conductive polymer, and the dispersion liquid is obtained. A step (A) of subjecting (1) to a dispersion treatment to obtain a dispersion liquid (2) containing the conjugated conductive polymer.
The step (B) of adhering the dispersion liquid (2) to a porous anode made of a valve acting metal having a dielectric film on the surface, and the aqueous dispersion liquid (2) adhering to the porous anode body. Step of removing the medium to form a solid electrolyte layer (C)
Have,
In the step (A), the operation of suspending the dispersion processing is performed once or more for a total of 1 to 6000 minutes, and the suspension time of one time is 1 to 300 minutes.
Manufacturing method of solid electrolytic capacitors. The method for producing a solid electrolytic capacitor according to claim 1, wherein seed particles protected and colloidalized by polyanions are dispersed in the aqueous medium. The method for manufacturing a solid electrolytic capacitor according to claim 1 or 2, wherein the operation of suspending the dispersion processing is performed 2 to 20 times. The method for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 3, wherein the time for suspending the dispersion treatment is 6 to 2250 minutes in total. The solid electrolytic capacitor according to any one of claims 1 to 4, wherein the viscosity of the dispersion liquid (1) after the suspension is 1.05 to 100.0 times the viscosity before the suspension. Production method. The method for producing a solid electrolytic capacitor according to any one of claims 1 to 5, wherein a salt compound is added to the dispersion liquid (1) in the step (A). The method for producing a solid electrolytic capacitor according to any one of claims 2 to 6, wherein the seed particles are particles of a polymer of an ethylenically unsaturated monomer. The method for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 7, wherein in the step (A), the dispersion treatment includes a dispersion treatment by ultrasonic irradiation. The method for producing a solid electrolytic capacitor according to any one of claims 1 to 8, wherein in the step (A), the dispersion treatment includes a dispersion treatment with a high-voltage homogenizer. The method for producing a solid electrolytic capacitor according to any one of claims 1 to 9, wherein the monomer compound is at least one selected from the group consisting of a pyrrole compound, an aniline compound, and a thiophene compound. The monomer compound has the following formula (1).

(In the formula, R ¹ and R ² each have an alkyl group and a substituent having 1 to 18 carbon atoms in a portion other than the substituent which may independently have a hydrogen atom, a hydroxyl group and a substituent. It represents an alkoxy group having 1 to 18 carbon atoms in a portion other than the substituent, or an alkylthio group having 1 to 18 carbon atoms in the portion other than the substituent which may have a substituent, or R ¹ and R. ^{In 2} , R ¹ and R ² are bonded to each other, and the portion other than the substituent which may have a substituent is an alicyclic having 3 to 10 carbon atoms, other than the substituent which may have a substituent. Aromatic ring having 6 to 10 carbon atoms, an oxygen atom-containing heterocycle having 2 to 10 carbon atoms other than the substituent which may have a substituent, and a substituent which may have a substituent. It represents a sulfur atom-containing heterocycle having 2 to 10 carbon atoms in the portion other than the substituent, or a sulfur atom-containing heterocycle having 2 to 10 carbon atoms in the portion other than the substituent which may have a substituent. )
The method for producing a solid electrolytic capacitor according to any one of claims 1 to 10, which is a compound represented by. The method for producing a solid electrolytic capacitor according to any one of claims 1 to 11, wherein the polyanion is a polymer having at least one of a group consisting of a sulfo group and a salt of a sulfo group. The invention according to any one of claims 1 to 12, wherein the polyanion is used in an amount such that the ratio of anionic groups in the polyanion is 0.25 to 30.00 mol with respect to 1 mol of the monomer compound. How to manufacture solid electrolytic capacitors. The method for producing a solid electrolytic capacitor according to any one of claims 1 to 13, wherein in the step (A), the polymerization is carried out using at least one oxidizing agent selected from peroxodisulfuric acid and a salt thereof. A monomer compound for obtaining a conjugated conductive polymer is polymerized in a liquid containing a polyanion and an aqueous medium to obtain a dispersion liquid (1) containing the conjugated conductive polymer, and the dispersion liquid is obtained. It has a step (A) of subjecting (1) to a dispersion treatment to obtain a dispersion liquid (2) containing the conjugated conductive polymer.
In the step (A), the operation of suspending the dispersion treatment is performed once or more for a total of 1 to 6000 minutes, and the suspension time of each time is 1 to 300 minutes. Dispersion containing a conjugated conductive polymer Method for producing liquid (2).

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